The US secretary of state Condoleezza Rice's meeting with Germany's new chancellor Angela Merkel tomorrow is likely to be a tricky affair. What should have been a chance to repair the damaging rift between the countries over Iraq is fast being eclipsed by something else - a new transatlantic row between the US and the European Union over the CIA.

During the weekend there were further revelations about the role of the CIA in kidnapping suspects. According to yesterday's Washington Post, the agency carried out a number of "erroneous renditions" - grabbing suspects off the street who later turned out to be innocent.

In total, "about three dozen" people may have been wrongly seized, the paper said. One of them was Khaled Masri - a German national who shared the same name as a top al-Qaida terrorist.

The CIA kidnapped him in Macedonia on Dec 31 2003, and flew him to Afghanistan, where he spent five months in appalling conditions. After realising its mistake, the administration debated whether to inform "the Germans" of the blunder, eventually dispatching the US ambassador to Germany, Daniel Coats, to tell the government, the paper said.

"They picked up the wrong people, who had no information. In many cases there was only some vague association with terrorism," one CIA officer told the Post. The embarrassing details are likely to increase pressure on Ms Rice to give a forthright account of the CIA's behaviour during her visit to Europe this week.

Yesterday the magazine Der Spiegel also gave further details that suggest that Europe was used as a major transit hub. It revealed that after September 11 2001, the CIA flew to Germany 437 times. Two CIA aircraft landed 132 and 146 times in 2002 and 2003 respectively, the magazine said, citing German government figures.

Ms Rice is not the only person with difficult questions to answer, however. European governments - who have so far been reluctant to confront Washington over the flights - now face awkward inquiries about how much they knew.

"If [EU] member or candidate states actively contributed to, or connived in, illegal transports and torture, or illegal prisons on their territory, that must be investigated and the necessary consequences drawn," Martin Schulz, head of the Socialist Group in the European Parliament, said yesterday. He added: 'There's active acceptance, and there's acquiescence. Neither of those are acceptable.'

According to the Post, the CIA operated a network of secret prisons or "black sites" in eight countries at various times, including several in eastern Europe. Since 9/11, the agency, often working with foreign partners, had captured an estimated 3,000 people, including several key al-Qaida leaders. Members of the rendition group would blindfold suspects, cut off their clothes, and administer an enema and sleeping drugs. They would transfer prisoners to one of the CIA's covert sites or to a detention facility in a friendly country - in Afghanistan, Central Asia or the Middle East. Things did not always go to plan, however. Mr Masri was kidnapped while the CIA's station chief in Macedonia was away on holiday. The American Civil Liberties Union is expected to announce tomorrow that it is suing the CIA in connection with his case. Others detained included an innocent college professor who had given an al-Qaida suspect a bad grade. "It was the Camelot of counter-terrorism. We didn't have to mess with others, and it was fun," an official working in the CIA's counter-terrorism centre told the Post.

Ms Merkel, who meets Condoleeza Rice in Berlin tomorrow, has said she wants a fresh start with the Bush administration, describing the row over Iraq as a "past battle". Ms Merkel's government played down expectations of revelations from the US. "We're not rushing things," a spokesman said. But the issue seems unlikely to go away. "If the US doesn't create any clarity ... then they feed suspicion and encourage speculation," said Mr Schulz. "If Ms Rice gives no clarification, we in parliament will further insist that the governments of the EU provide this clarification themselves."

Backstory

The American policy of moving suspects from one country to another without any court hearing or extradition process is thought to have begun in the Reagan era. In those days, joint CIA and FBI teams would bring drug traffickers and terrorism suspects to the United States. They would be read their rights, given lawyers and then put on trial. In the wake of the 1993 bomb attack on the World Trade Centre, these detentions, known as "renditions", were largely replaced by the "extraordinary rendition" policy of taking suspects to a third country. CIA officers combating Islamist terrorism decided they should keep some suspects out of the US courts for fear of jeopardising their sources and to protect intelligence officials from other countries who did not wish to be called as witnesses. Michael Scheuer, a former CIA counter-terrorism expert, has explained how he approached Clinton administration officials for permission. "They said, 'Do it'." While it is against US law to take anyone to a country where there are "substantial grounds" for believing they will be tortured, those officials are said to have relied upon a very precise reading of that term, arguing that they could not be sure whether suspects would be tortured or not. At least four suspected Islamists were subsequently abducted in the Balkans in the late 1990s and taken to Egypt. One disappeared, two are reported to have been executed and one later alleged that he was tortured. An Islamist organisation threatened retaliation for these abductions and two days later, the US embassies in Tanzania and Kenya were blown up, killing 224 people. The Bush administration reviewed and renewed the presidential directive which authorises the rendition programme, and after the terrorist attacks of 9/11, the number of abductions rocketed. According to Scott Horton, an international law specialist who helped prepare a report on renditions published by the New York University School of Law and the New York City Bar Association, as many as 150 people have been "rendered" over the past four years. Most of these people have not been charged with any crime.

They are denied lawyers, their families do not know their whereabouts and their detention is concealed from the international committee of the Red Cross.